Photochromic materials that show photochromism in which coloring/decoloring occurs by a photoreaction have been used mainly for light-modulating dyes for sunglasses, and the like. Furthermore, studies are proceeding with recording materials such as optical disks and display materials such as holograms.
In light-modulating materials for sunglasses, spiropyran-based compounds, naphtopyran-based compounds, fulgide-based compounds, diarylethene-based compounds and the like have been used, but there were disadvantages that they have low decoloration reaction velocities at a room temperature, for example, the color remains for a while after moving from outside to inside, the color does not go out even one enters a tunnel while driving and restoration of the eyesight in front is delayed, and the like.
Under such situation, as shown in Non-Patent Literature 1 (first generation HABI) and Non-Patent Literature 2 (second generation HABI), the inventors have developed radical diffusion-inhibited photochromic molecules whose decoloring reactions are extremely quick and the half-lives of colored bodies are short times in increments of milliseconds.